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Grounding shielding around motor cable

Posted: Wed, 30 Oct 2019, 03:56
by soyachips
The cables that comes out of my hub motor have shielding around them and someone recently said I should ground the shielding to the bike frame. Is this correct and are there any tricks to doing this?

Re: Grounding shielding around motor cable

Posted: Wed, 30 Oct 2019, 09:34
by jonescg
Check for continuity between the shield and the motor chassis. If there is none, that's good - it means you can connect the shielding cable to the same shield as your BMS communications. You want to minimise any potential ground loops, so have all shields meet at the same point if possible.

Re: Grounding shielding around motor cable

Posted: Wed, 30 Oct 2019, 12:54
by Richo
Power wires or signal wires?

Metal gland.
Usually this is done at the source (motor controller).
You really should check that they have no continuity to any of the wires.
Otherwise you could earth your ground...

Re: Grounding shielding around motor cable

Posted: Wed, 06 Nov 2019, 05:12
by bladecar
I wonder if there should be a separate listing on this site for "technical assistance" in order to separate those dedicated to technical matters from those dedicated to Australian Electric Vehicles.

Re: Grounding shielding around motor cable

Posted: Wed, 06 Nov 2019, 06:48
by jonescg
I think it resides in the correct forum 😕

Re: Grounding shielding around motor cable

Posted: Wed, 06 Nov 2019, 12:46
by Richo
Mmmm the "help me I'm stuck" page :lol:

Only people with pace makers worry about EMC :lol: :o

Re: Grounding shielding around motor cable

Posted: Wed, 11 Dec 2019, 13:15
by Rusdy
I'm still confused with 'ground loops'. I thought 'ground loops' only happens when there is a poor ground connection (or long distance wiring). So, when current induces on the cable shield, it will in turn induce current to signal wire.

So, if you have good ground (such as car or bike's frame), then, in theory, you can 'ground' the shield to your heart's content, right?

The more I read about this, the more confused I am, example, this link.

Re: Grounding shielding around motor cable

Posted: Wed, 11 Dec 2019, 18:09
by brunohill
I think Rudsy at lower frequencies this is still the case, but these days we are using higher frequency AC, digitally clipping it producing harmonics and actually producing RF radiation as distinct from just induction problems.